Trichoscopy of Scalp Folliculotropic Mycosis Fungoides: A Review of the Literature

Background: Mycosis fungoides (MF) is the most common type of T-cell lymphoma and is characterized by the infiltration of the epidermis by small to medium-sized atypical T lymphocytes. Folliculotropic MF (FMF) is a rare clinicopathological variant of MF characterized by preferential infiltration of the follicular epithelium. Clinical presentation of FMF can vary from follicle-based patches to plaques, nodules, and tumors, with cicatricial or not alopecia. The most involved site is the head, especially the face. Objective: The aim of this review was to assess the main trichoscopic findings reported in scalp lesions. Methods: A comprehensive literature search of PubMed was performed. Results: Ten studies were included; the trichoscopic features reported were decreased number of pilosebaceous units, dotted dilated vessels, white/yellow scales, and perifollicular halos. The main clinical presentation reported were patchy alopecia or generalized alopecia. Most of the studies included were case reports, so studies with larger sample sizes are strongly needed to make trichoscopy a complementary diagnostic tool to improve the differential diagnoses between FMF and other scalp disorders. Conclusion: Trichoscopy plays a key role in diagnosing FMF of the scalp, revealing characteristic features such as milky-red globules, orange-yellow patches, comedones, and distinct vascular patterns.